.df{
    display: flex;
}
.ais-c{
    align-items: center;
}
.jt-c{
    justify-content: center;
}
.fd-r{
    flex-direction:row;
}
.fd-c{
    flex-direction:column;
}
.fw-n{
    flex-wrap:nowrap;
}
.fw-w{
    flex-wrap:wrap;
}
.fw-wr{
    flex-wrap:wrap-reverse;
}
.ff-rn{
    flex-flow:row nowrap;
}